Improvement in lift-bridges



3 Sheets-She et l. S. SWA R T Z.-

LIFT-BRIDGE. No.17Z,z04. I Patented Jan. 11,1876.

WITN ESSES INVENTOR MISTERS, FHOTO-LITHOGRAFHER, WASHINGTON, I10.

3 Sheets-Sheet 2.

s. SWARTZ.

' LIFT-BRIDGE. No.17Z,Z04. Patented Jan. 11,1876.

'WITNESS INYENTOR ILPEI'ERS. PHOTO-LITHOGRAFHERfl WIKQ-IINGYON, 0. C-

' SSheets-Sheet3. S. SWARTZ.

LIFT-BRIDGE. No.17Z,ZO4.

Patented Jan.11,18'76 WITNESSES INVENTOR ILPEIERS. FHOTU-UTHOGRAFHER,WASHINGTON. D Q

UNITED 1 STATES PATENT OFFICE.

' sAMUEL swAETz, or BUFF LO, NEW YORK, ssIcNoE r0 JULIA SWARTZ, OF sAMEPLACE.

IMPROVEMENT IN LIFT-BRIDGES.

Specification forming part of Letters Patent N 0. 172,204, dated January11,1876; application filed July 8, 1875.

To all whom it may concern:

Be'it known that I, SAMUEL SWARTZ, of Bufi'alo, in the county of Erieand State of New York, have invented certain new and useful Improvementsin Lift-Bridges, of which the following is a specification Thisinvention is more especially designed for. highway and railroad bridges,with or without sidewalks, over canals and like narrow water-ways.

The improvements comprise, first, a device for counterbalancing thebridge and regulating the force and delicacy of the counter-balance;second, acombination and arrangement of devices for operating thebridge.

In the accompanying drawing, Figure 1 is a plan view of a bridgeillustrating the invention. Fig. 2 is a longitudinal section on the line2, Fig. 1. Fig. 3 is a transverse section on the line 3, Figs. 1 and 2.Fig. 4 is a perspective view of a counterbalance-weight.

The foundation A A of the bridge can be made of piles and timber, or ofmasonry, as preferred. B representsthe roadway of the bridge proper,sustained by a truss, G, of any usual and suitable construction, andflanked by sidewalks D D, if preferred. E E represent guard-rails. Thebridge proper turns vertically on a horizontal pivot-shaft, F, securelyfastened on its journal-bearings in pillar-blocks G. The heel end of thebridge B C is secured to the pivot-shaft F, the truss being made toextend beyond the said shaft to the distance of about one-third thelength of the span of the bridge, for the purpose of attaching thebalance-boxes H, by which the bridge is counterbalanced. I I representthe extension-arms, and J the brace or stay rods, firmly connected attheir respective ends to the said extension-arms and to the crown of thearch, and passing over struts K, so as to support the heel-extension,and constituterit a part of the truss. The balance-boxes H are hung onpivot-studs L, projecting from slides M, which, by means of screws N,are adjusted up or down in the solid ends I of the arms I, to adapt theweights to properly counterbalance the bridge when in averticalposition.

The vertical adjustment of the counterbalance-weights may be effected byracks and pinions, if preferred, or by graduating-holes for the slidesor boxes M, to which the weights are pivoted, or by hinging the lowercords or arms I near the pivot-shaft F, and lengthening or shorteningthe upper cords or stayrods J, so as to lower or raise the weights.

The counterbalance apparatus works within a water-tight curb, 0,constructed of masonry or wood, or of sheet metal, below the water-line,so that the roadway of the bridge may be placed as low as desirable.

It is preferred to construct the water-tight curbs of boiler-iron ofsufficient strength to resist the pressure of water from the outside.

For the purpose of raising the bridge, the pivot-shaft F is extended tothe outside, and has keyed to its extremity a segment spurwheel, P, withwhich gears a pinion, Q, on a counter-shaft, R, on theother end of whichis a bevelwheel, S, driven by a bevel-pinion, T, on the vertical shaftU, passing just above the floor, and receiving a lever-arm, V, which isoperated in the usual manner.

The multiplying gearing here shown will enable the operator to raise thebridge in about one-half a minute, walking at a moderate pace.

The manner of raising and lowering the bridge will be clearly understoodfrom the foregoing description of the construction of the parts.

To regulate the counterbalancing of the bridge the counterbalance-weights are adjusted up or down. The leverage and friction in thehoisting machinery will ordinarily hold the bridge set While itisexactly counterbalanced.

If more steadiness be desired, weight should be removed from thecounterbalance boxes H, and added to the toe or extremity of the bridge,so as to seat the bridge more firmly when closed. The'boxes are thenraised by the screws Nor other means, as set forth, so that when thebridge is elevated to the vertical position shown in dotted lines inFig. 2,

the counterbalance-boxes will be more nearly underneaththe pivot-shaftF. This causes the bridge to be set more firmly when open.

The following is claimed as new: 1. A lift-bridge constructed with acounterbalance weight or weights, adjustable verti-' bridge B O,extension-truss I J, and countercally in the horizontal position of thebridge, balance-weights H, substantially as and. for to regulate theeffect of said weight or weights the purpose'set forth.

on the bridge when in its vertical position,

substantially as set forth. SAMUEL SWARTZ.

2. The combination of the horizontal pivot- Witnesses: shaft F,counter-shaft R, vertical shaft U, 1e GEORGE W. TOWNSEND,

ver V, and gearing P Q S T with thelift- ARTHUR W. HICKMAN.

